Satish, K. and Gutema, Z. and Grenier, C. and Rich, P.J. and Ejeta, G. (2012) Molecular tagging and validation of microsatellite markers linked to the low germination stimulant gene (lgs) for Striga resistance in sorghum [Sorghum bicolor (L.) Moench}. TAG Theoretical and Applied Genetics, 124 (6). pp. 989-1003.
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Abstract
Striga is a devastating parasitic weed in Africa and parts of Asia. Low Striga germination stimulant activity, a well-known resistance mechanism in sorghum, is controlled by a single recessive gene (lgs). Molecular markers linked to the lgs gene can accelerate development of Striga-resistant cultivars. Using a high density linkage map constructed with 367 markers (DArT and SSRs) and an in vitro assay for germination stimulant activity towards Striga asiatica in 354 recombinant inbred lines derived from SRN39 (low stimulant) 9 Shanqui Red (high stimulant), we precisely tagged and mapped the lgs gene on SBI-05 between two tightly linked microsatellite markers SB3344 and SB3352 at a distance of 0.5 and 1.5 cM, respectively. The fine-mapped lgs region was elimited to a 5.8 cM interval with the closest three markers SB3344, SB3346 and SB3343 positioned at 0.5, 0.7 and 0.9 cM, respectively. We validated tightly linked markers in a set of 23 diverse sorghum accessions, most of which were known to be Striga resistant, by genotyping and phenotyping for germination stimulant activity towards both S. asiatica and S. hermonthica. The markers co-segregated with Striga germination stimulant activity in 21 of the 23 tested lines. The lgs locus similarly affected germination stimulant activity for both Striga species. The identified markers would be useful in marker-assisted selection for introgressing this trait into susceptible sorghum cultivars. Examination of the sorghum genome sequence and comparative analysis with the rice genome suggests some candidate genes in the fine-mapped region (400 kb) that may affect strigolactone biosynthesis or exudation. This work should form a foundation for map-based cloning of the lgs gene and aid in elucidation of an exact mechanism for resistance based on low Striga germination stimulant activity.
| Item Type: | Article |
|---|---|
| Additional Information: | We gratefully acknowledge financial support from the United States Agency for International Development (USAID) INTSORMIL grant #EPP-A-0006-00016-00. |
| Uncontrolled Keywords: | Striga, Sorghum, Molecular Tagging |
| Author Affiliation: | Department of Agronomy, Purdue University, 915 W State Street, West Lafayette, IN 47907-2054, USA |
| Subjects: | Plant Protection Crop Improvement |
| Divisions: | Sorghum |
| Depositing User: | Mr Siva Shankar |
| Date Deposited: | 19 Dec 2011 08:40 |
| Last Modified: | 04 Sep 2012 06:04 |
| Official URL: | http://dx.doi.org/10.1007/s00122-011-1763-9 |
| URI: | http://eprints.icrisat.ac.in/id/eprint/2852 |
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